Portable burglar alarm



May 26, 1942.

C. METZLER PORTABLE BURGLAR ALARM Filed Sept. 13, 1938 Patented May 26, 1942 I UNITED STATES PATENT OFFICE,"

PORTABLE BURGLAR ALARM Charles Metzler, Cincinnati, Ohio Application September 13, 1938, Serial No. 229,720

1 Claim.

My invention relates to burglar alarms oi the type adapted to give an electrically actuated warning signal.

The principal object of the present invention is to provide an electrically operated burglar alarm of a type readily portable and which may be easily installed without previous experience or training so as to be actuated by the surreptitious opening of a hotel door or other place of temporary lodgment.

With the above and other objects in mind as will more fully hereinafter appear, my device consists of an electrically operated bell, battery and a switch which may be temporarily secured between a door and its jamb, and which, upon the opening of the door is adapted automatically to close the circuit between said battery and bell to give warning of such opening; all of said parts being adapted furthermore for enclosure in a small and readily portable housing which may be conveniently included in a travelers grip or suitcase.

In the drawings:

Figure l is a perspective of my new burglar alarm showing the bell, battery and electrical connections, together with the compartment for housing the automatic switch when the device is not in use;

Figure 2 is an elevation of the automatic switch;

Figure 3 is a perspective illustrating the manner of attaching the switch;

Figure 4 is a diagram of the electrical circuit.

Figure 5 is a section showing the attachment.

The numeral l indicates a metal case or housing having a hinged cover 2, which may be secured when closed by locking means 3-3. The case I is divided into a large compartment 4 and a smaller compartment 5 by means of a longitudinal partition 6. Mounted in the compartment 4 are an electric bell 1, battery 8, which is of the small dry cell type, manually operated switch 9, binding posts III and II for connection of the automatic switch, together with the necessary electrical connections between said elements, said connections being illustrated diagrammatically in Figure 4 hereinafter more fully referred to.

The smaller compartment 5 is adapted to receive, when the device is not in use, the automatic switch I2, see Figure 2,.together with the electrical cord I3 by means of which the switch I2 is connected to the binding posts It and I I.

The automatic switch I2 consists of two electrically conductive arms I4 and I5 which are hinged together by means of a pintle I6; a spring I'I coiled around the pintle I6 and with its ends secured to the respective arms I4 and I5, tends normally to press said arms together so as to make contact between a terminal I8, mounted on but insulated from, arm I l and a terminal I9 on thearm I5. The respective leads of cord I3 are connected with the terminal I8 and a binding post 26 which is electrically in circuit with the arm I4 and thus with arm I5 and terminal IS; the other ends of said leads are secured to the binding posts I0 and II as above set forth.

In Figure 4 the various electrical connections above described are illustrated diagrammatically. From said figure it will be seen that the manually operated switch 9 is in circuit between the battery and bell, and that such switch must first be closed before the bell becomes operable by the closure of the automatic switch I2; this switch 9 is thus provided to prevent the signal from operating when not desired for the reason that the automatic switch is normally held in closed position by means of the spring ll. When both switch 9 and switch l2 are closed however, it will be seen that a circuit from said battery, through switch 9, bell 1, binding post It, switch I2, post II and back to the battery is completed, thus operating the bell.

In use, the arm I5 of the automatic switch I2 is inserted between the door and jamb, the two arms of the switch being separated against the compression of spring Il to permit this to be done; in this position of arm I5, arm I4 rests against the door frame. The door then being closed upon arm I5, the switch is held in open position. When so set the manual switch 9 is closed. When the switches are thus set it will be observed that opening the door will release arm I5 permitting the automatic switch to close and thus to complete the battery-bell circuit.

From the foregoing it will be seen that a conveniently portable alarm device is provided which makes readily available to travelers and others occupying temporary lodgings complete protection against the surreptitious opening the door or doors to such lodgings. It will be understood that Where desired a plurality of automatic switches of the type described may be provided the same to be connected in parallel in the battery-bell circuit so that the signal may be operated by either of such switches.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

In a device of the character specified a switch comprising two conductive arms, a conductive pintle upon which said arms are pivotally mounted, an electrical terminal mounted on one of said arms, a second terminal mounted on the other arm, means for insulating said second terminal from the arm on which it is mounted, the terminal bearing end of one of said arms being adapted to be inserted and held between movable and immovable building members and the terminal bearing end of the other arm being adapted to rest against the surface of one of said building members, whereby angularly disposed planes of one of said members are slidably engaged by said arms, a spring mounted on said pintle with its respective ends attached to the respective arms so as normally to force the terminal bearing ends of said arms together whereby upon the movement of said movable building member, said ends are compressed so as to force said arms away from said members and to cause said terminals 10 to contact.

CHARLES METZLER. 

